PC case swap?

[AllAussie]

Major specifications:
i7 6700 CPU
Asus Z170-AR MotherB
Corsair RM750
GTX 980ti (currently needing replacement)

Currently running my PC with the above specs. I want to swap the case for a bigger ones. I can only fit 2 fans in my current case as well as a h80i cpu water cooling system. Hoping to swap out for a corsair 900D and full watercooling system in future. What is the best way to do this? Should I go to an it department or attempt this myself. I have replaced parts in the past but never moved an entire system into another case. Any help would be great

 

[USAFRet]

Much better for you to do it, rather than some monkey at the store.
Especially if you are looking for some odd or extensive liquid cooling setup.

You'll take MUCH better care of it than he would.